Why We Don’t Perform Radon Gas Testing in San Diego
Radon is a colorless, odorless, and tasteless gas that is present in varying amounts in the ground and in water. Radon is produced by the natural radioactive decay of uranium deposits in the earth. Prolonged exposure to radon in high concentrations can cause cancer. The EPA has set guidelines for radon levels in residential buildings. 
The EPA recommends that mitigation measures be undertaken in residential buildings when radon concentrations are 4 picocuries per liter (4 pCi/L) of air and above. The radon concentration in a house varies with time and is affected by the uranium-radium content in the soil, the geological formation beneath the house, the construction of the house, rain, snow, barometric pressure, wind, and pressure variations caused by the periodic operation of exhaust fans, heating systems, fireplaces, attic fans, and range fans. Radon concentrations are variable and may be high in one house and low in an adjacent house. To determine if a house has a radon problem, it must be tested.
The EPA has mapped out Radon and divided the country into Zones. The map for California can be found by clicking HERE. San Diego is in a Zone with low amounts of Radon Gas. San Diego is in Zone 3 with predicted indoor Radon levels of less than 2 pCi/L which is less than the level at which the EPA considers it a hazard. To confirm these readings, The Real Estate Inspection Company placed 12 Radon Gas monitors throughout the county to get independent readings. What we found confirms the EPA conclusions that there is no significant risk of Radon Gas exposure in the area.
Another reason for the low risk of Radon in our area is that most homes are slab-on-grade, and those built since the 1980’s almost always have a moisture barrier under the slab. This barrier will prevent radon gas from infiltrating a home.
Most home inspectors do not offer Radon testing in San Diego. Those that do are simply charging for a service that is not needed. According to the EPA, the test results would almost certainly come back negative. There are some home inspectors who will test for Radon.
Test: A long-term test is the most accurate method of determining the average annual radon concentration. However, because time is usually limited, there is a three- to seven-day test that uses a charcoal canister or electronic air testing. It is available from most home do-it-yourself stores or through radon testing service companies.
